Difficulty Control is a mod that adds two new options to the game. The first one is called "Modify damage taken by player and creatures". If you enable it, then you can set the player's and the creatures' damage multiplier to a value that you want.

The second one is called "Base multipliers". If you enable it, then you can set the player's base multiplier to a value that you want.

These two options are the only ones that are currently available. If you want to know what the others are, then you can check the source code on GitHub.